Given the positive reaction to my study of the great slugging teams, I thought I'd take a look at the teams with the greatest on base percentages in a single season, relative to the league. This time, I'll just run the "modern" teams rather than the too-old-time-to-be-quite-legitimate teams, drawing the line at 1893, the point at which the pitching conditions (mound distance, number of balls for a walk) and length of the season started more nearly resembling the modern game. Here are the 19 post-1893 teams that finished at least 9% above the league:

A few things jumped off the page here. First, the teams that dominate the OBP category have done so by a far narrower margin than the great slugging teams; we've got just seven teams here, and just three since 1910, that finished more than 10% better than the league, whereas the top slugging teams were in the 15-22% range. Second, as Rob Neyer and others love to point out, slugging and OBP go together like chocolate and peanut butter: 7 of the top 10 modern slugging teams reappear here (including a reprise by the unheralded 1965 Reds). Another of those teams, the 1950 Red Sox, just missed the cut (beating the league OBP by 8.2%), but is tied for the highest team OBP of the 20th century (.382, tied with the 1930 Yankees and 1921 Tigers; you can run the decimal places and tell me who comes out ahead if you like; the 1894 Phillies, with four .400 hitting outfielders, and 1894 Orioles remain the only teams ever to crack the .400 barrier). Third, the name "John McGraw" comes to mind: McGraw played for three of these teams and managed three others (credit should be shared with Hugh Jennings, who got drilled by 40-50 pitches a year for those Orioles teams, and with Roger Bresnahan, the on-base star of the Mathewson-era Giants). Other teams on the list make you think instantly of Babe Ruth, Earl Weaver (Weaver's 1971 O's are known for four 20-game winners, but a .422 OBP from Merv Rettenmund and a .365 OBP from Mark Belanger had more than a little to do with that), Ty Cobb (the 1915 Tigers didn't have the top 3 in the league in RBI for nothing), and Wade Boggs. There are also remarkably few recent teams, which makes the 1976 Reds' dominance that much more impressive. And, of course, there's an awful lot of pennant-winning teams here, as you'd have guessed.

Although one suspects that the repeat presence of McGraw teams suggests that -- as analysts today would argue -- a focus on OBP can be a choice, the fact that the leagues have often been quite compressed (the 1980 National League is one extreme example, with the Cardinals' .329 league-leading figure compared to a league average of .321) would suggest that even without thinking about OBP, managers have mostly stayed within a narrow band in assembling their teams. On the other hand, even a 5-7% advantage in OBP can mean a lot of runs. And it does seem that the spreads are widening in recent seasons, with the 2001 Mariners beating the AL average by 9.4%, the 2002 Yankees by 8.3%, and the 2003 Red Sox by 8.4% through Tuesday, and the 2001 Rockies leading the NL by 8.3% (the biggest margin of the 1990s was actually the 1994 Yankees at 8.4%).

For what it's worth, the top old-time teams were the 1876 Chicago White Stockings, 27.4% above the league at .353 compared to a league average of .277, and the 1875 Boston Red Stockings of the National Association, 24.9% above the league; the top legitimate (non-Union Association) 1880s team was the 1886 Chicago White Stockings, 16% above the league. One reason I included the 1890s teams in the list above rather than lumping them back here was that I had a hard time convincing myself that the game played by the 1897-98 Orioles was really that different from the game played by the 1902 Pirates or the 1905 Giants.